diff --git a/tiramisu/autolib.py b/tiramisu/autolib.py
index 500f99f..c920be9 100644
--- a/tiramisu/autolib.py
+++ b/tiramisu/autolib.py
@@ -21,7 +21,7 @@
 from .error import PropertiesOptionError, ConfigError, SlaveError, display_list
 from .i18n import _
 from .setting import undefined
-from .option.baseoption import DynSymLinkOption
+from .option.symlinkoption import DynSymLinkOption
 from .storage import get_default_values_storages, get_default_settings_storages
 # ____________________________________________________________
 
diff --git a/tiramisu/option/__init__.py b/tiramisu/option/__init__.py
index d770343..af12525 100644
--- a/tiramisu/option/__init__.py
+++ b/tiramisu/option/__init__.py
@@ -2,7 +2,8 @@ from .optiondescription import OptionDescription
 from .dynoptiondescription import DynOptionDescription
 from .syndynoptiondescription import SynDynOptionDescription
 from .masterslave import MasterSlaves
-from .baseoption import SymLinkOption, DynSymLinkOption, submulti
+from .baseoption import submulti
+from .symlinkoption import SymLinkOption, DynSymLinkOption
 from .option import Option
 from .choiceoption import ChoiceOption
 from .booloption import BoolOption
diff --git a/tiramisu/option/baseoption.py b/tiramisu/option/baseoption.py
index 7a3f043..eeb9033 100644
--- a/tiramisu/option/baseoption.py
+++ b/tiramisu/option/baseoption.py
@@ -20,23 +20,18 @@
 # ____________________________________________________________
 import re
 from types import FunctionType
-import sys
 import weakref
+from inspect import signature
 
 from ..i18n import _
 from ..setting import undefined
 from ..error import ConfigError
 
-if sys.version_info[0] >= 3:  # pragma: no cover
-    from inspect import signature
-else:
-    from inspect import getargspec
-
 STATIC_TUPLE = frozenset()
 
 
 submulti = 2
-NAME_REGEXP = re.compile(r'^[a-z][a-zA-Z\d_]*$')
+NAME_REGEXP = re.compile(r'^[a-z][a-zA-Z\d_-]*$')
 FORBIDDEN_NAMES = frozenset(['iter_all', 'iter_group', 'find', 'find_first',
                              'make_dict', 'unwrap_from_path', 'read_only',
                              'read_write', 'getowner', 'set_contexts'])
@@ -53,7 +48,10 @@ def valid_name(name):
             not name.startswith('cfgimpl_')
 
 
-def validate_callback(callback, callback_params, type_, callbackoption):
+def validate_callback(callback,
+                      callback_params,
+                      type_,
+                      callbackoption):
     """validate function and parameter set for callback, validation, ...
     """
     def _validate_option(option):
@@ -67,7 +65,8 @@ def validate_callback(callback, callback_params, type_, callbackoption):
         else:
             raise ValueError(_('{}_params must have an option'
                                ' not a {} for first argument'
-                              ).format(type_, type(option)))
+                              ).format(type_,
+                                       type(option)))
         if cur_opt != callbackoption:
             cur_opt._add_dependency(callbackoption)
             callbackoption._has_dependency = True
@@ -77,8 +76,8 @@ def validate_callback(callback, callback_params, type_, callbackoption):
         if not isinstance(force_permissive, bool):
             raise ValueError(_('{}_params must have a boolean'
                                ' not a {} for second argument'
-                              ).format(type_, type(
-                                  force_permissive)))
+                              ).format(type_,
+                                       type(force_permissive)))
 
     def _validate_callback(callbk):
         if isinstance(callbk, tuple):
@@ -135,12 +134,19 @@ class Base(object):
                  '__weakref__'
                 )
 
-    def __init__(self, name, doc, requires=None, properties=None, is_multi=False):
+    def __init__(self,
+                 name,
+                 doc,
+                 requires=None,
+                 properties=None,
+                 is_multi=False):
         if not valid_name(name):
             raise ValueError(_('invalid name: "{0}" for option').format(name))
         if requires is not None:
-            calc_properties, requires = validate_requires_arg(self, is_multi,
-                                                              requires, name)
+            calc_properties, requires = validate_requires_arg(self,
+                                                              is_multi,
+                                                              requires,
+                                                              name)
         else:
             calc_properties = frozenset()
             requires = undefined
@@ -150,9 +156,8 @@ class Base(object):
             properties = tuple(list(properties) + ['empty'])
         if not isinstance(properties, tuple):
             raise TypeError(_('invalid properties type {0} for {1},'
-                              ' must be a tuple').format(
-                                  type(properties),
-                                  name))
+                              ' must be a tuple').format(type(properties),
+                                                         name))
         if calc_properties != frozenset([]) and properties is not tuple():
             set_forbidden_properties = calc_properties & set(properties)
             if set_forbidden_properties != frozenset():
@@ -161,8 +166,6 @@ class Base(object):
                                      list(set_forbidden_properties)))
         _setattr = object.__setattr__
         _setattr(self, '_name', name)
-        if sys.version_info[0] < 3 and isinstance(doc, str):
-            doc = doc.decode('utf8')
         _setattr(self, '_informations', {'doc': doc})
         if calc_properties is not undefined:
             _setattr(self, '_calc_properties', calc_properties)
@@ -171,16 +174,12 @@ class Base(object):
         if properties:
             _setattr(self, '_properties', properties)
 
-    def _build_validator_params(self, validator, validator_params):
-        if sys.version_info[0] < 3:
-            func_args = getargspec(validator)
-            defaults = func_args.defaults
-            if defaults is None:
-                defaults = []
-            args = func_args.args[0:len(func_args.args)-len(defaults)]
-        else:  # pragma: no cover
-            func_params = signature(validator).parameters
-            args = [f.name for f in func_params.values() if f.default is f.empty]
+    def _build_validator_params(self,
+                                validator,
+                                validator_params):
+
+        func_params = signature(validator).parameters
+        args = [f.name for f in func_params.values() if f.default is f.empty]
         if validator_params is not None:
             kwargs = list(validator_params.keys())
             if '' in kwargs:
@@ -206,7 +205,8 @@ class Base(object):
             validator_params[''] = tuple(params)
         return validator_params
 
-    def impl_has_dependency(self, self_is_dep=True):
+    def impl_has_dependency(self,
+                            self_is_dep=True):
         if self_is_dep is True:
             if self.impl_is_master_slaves():
                 return True
@@ -214,7 +214,8 @@ class Base(object):
         else:
             return hasattr(self, '_dependencies')
 
-    def _get_dependencies(self, context):
+    def _get_dependencies(self,
+                          context):
         if context:
             od = context.cfgimpl_get_description()
         ret = set(getattr(self, '_dependencies', STATIC_TUPLE))
@@ -223,12 +224,17 @@ class Base(object):
         else:
             return ret
 
-    def _add_dependency(self, option):
+    def _add_dependency(self,
+                        option):
         options = self._get_dependencies(None)
         options.add(weakref.ref(option))
         self._dependencies = tuple(options)
 
-    def impl_set_callback(self, callback, callback_params=None, _init=False):
+    def impl_set_callback(self,
+                          callback,
+                          callback_params=None,
+                          _init=False):
+
         if callback is None and callback_params is not None:
             raise ValueError(_("params defined for a callback function but "
                                "no callback defined"
@@ -237,9 +243,13 @@ class Base(object):
         if not _init and self.impl_get_callback()[0] is not None:
             raise ConfigError(_("a callback is already set for {0}, "
                                 "cannot set another one's").format(self.impl_getname()))
-        self._validate_callback(callback, callback_params)
+        self._validate_callback(callback,
+                                callback_params)
         if callback is not None:
-            validate_callback(callback, callback_params, 'callback', self)
+            validate_callback(callback,
+                              callback_params,
+                              'callback',
+                              self)
             val = getattr(self, '_val_call', (None,))[0]
             if callback_params is None or callback_params == {}:
                 val_call = (callback,)
@@ -281,7 +291,8 @@ class Base(object):
             if extra is not None:
                 _setattr(self, '_extra', tuple([tuple(extra.keys()), tuple(extra.values())]))
 
-    def _impl_setsubdyn(self, subdyn):
+    def _impl_setsubdyn(self,
+                        subdyn):
         self._subdyn = weakref.ref(subdyn)
 
     def impl_getrequires(self):
@@ -299,16 +310,15 @@ class Base(object):
 
     # ____________________________________________________________
     # information
-    def impl_get_information(self, key, default=undefined):
+    def impl_get_information(self,
+                             key,
+                             default=undefined):
         """retrieves one information's item
 
         :param key: the item string (ex: "help")
         """
         def _is_string(infos):
-            if sys.version_info[0] >= 3:  # pragma: no cover
-                return isinstance(infos, str)
-            else:
-                return isinstance(infos, str) or isinstance(infos, unicode)
+            return isinstance(infos, str)
 
         dico = self._informations
         if isinstance(dico, tuple):
@@ -325,7 +335,9 @@ class Base(object):
         raise ValueError(_("information's item not found: {0}").format(
             key))
 
-    def impl_set_information(self, key, value):
+    def impl_set_information(self,
+                             key,
+                             value):
         """updates the information's attribute
         (which is a dictionary)
 
@@ -334,11 +346,10 @@ class Base(object):
         """
         if self.impl_is_readonly():
             raise AttributeError(_("'{0}' ({1}) object attribute '{2}' is"
-                                   " read-only").format(
-                                       self.__class__.__name__,
-                                       self,
-                                       #self.impl_getname(),
-                                       key))
+                                   " read-only").format(self.__class__.__name__,
+                                                        self,
+                                                        #self.impl_getname(),
+                                                        key))
         self._informations[key] = value
 
 
@@ -352,7 +363,9 @@ class BaseOption(Base):
     def __getstate__(self):
         raise NotImplementedError()
 
-    def __setattr__(self, name, value):
+    def __setattr__(self,
+                    name,
+                    value):
         """set once and only once some attributes in the option,
         like `_name`. `_name` cannot be changed one the option and
         pushed in the :class:`tiramisu.option.OptionDescription`.
@@ -373,14 +386,14 @@ class BaseOption(Base):
                 is_readonly = self.impl_is_readonly()
             if is_readonly:
                 raise AttributeError(_("'{0}' ({1}) object attribute '{2}' is"
-                                       " read-only").format(
-                                           self.__class__.__name__,
-                                           self,
-                                           #self.impl_getname(),
-                                           name))
+                                       " read-only").format(self.__class__.__name__,
+                                                            self,
+                                                            #self.impl_getname(),
+                                                            name))
         super(BaseOption, self).__setattr__(name, value)
 
-    def impl_getpath(self, context):
+    def impl_getpath(self,
+                     context):
         return context.cfgimpl_get_description().impl_get_path_by_opt(self)
 
     def impl_has_callback(self):
@@ -390,23 +403,19 @@ class BaseOption(Base):
     def _is_subdyn(self):
         return getattr(self, '_subdyn', None) is not None
 
-    def _impl_valid_unicode(self, value):
-        if sys.version_info[0] >= 3:  # pragma: no cover
-            if not isinstance(value, str):
-                return ValueError(_('invalid string'))
-        else:
-            if not isinstance(value, unicode) and not isinstance(value, str):
-                return ValueError(_('invalid unicode or string'))
+    def _impl_valid_string(self,
+                           value):
+        if not isinstance(value, str):
+            return ValueError(_('invalid string'))
 
-    def impl_get_display_name(self, dyn_name=None):
+    def impl_get_display_name(self,
+                              dyn_name=None):
         name = self.impl_getdoc()
         if name is None or name == '':
             if dyn_name is not None:
                 name = dyn_name
             else:
                 name = self.impl_getname()
-        if sys.version_info[0] < 3 and isinstance(name, unicode):
-            name = name.encode('utf8')
         return name
 
     def reset_cache(self,
@@ -432,7 +441,10 @@ class OnlyOption(BaseOption):
     __slots__ = tuple()
 
 
-def validate_requires_arg(new_option, multi, requires, name):
+def validate_requires_arg(new_option,
+                          multi,
+                          requires,
+                          name):
     """check malformed requirements
     and tranform dict to internal tuple
 
@@ -454,7 +466,13 @@ def validate_requires_arg(new_option, multi, requires, name):
         option._add_dependency(new_option)
         return option
 
-    def _set_expected(action, inverse, transitive, same_action, option, expected, operator):
+    def _set_expected(action,
+                      inverse,
+                      transitive,
+                      same_action,
+                      option,
+                      expected,
+                      operator):
         if inverse not in ret_requires[action]:
             ret_requires[action][inverse] = ([(option, [expected])], action, inverse, transitive, same_action, operator)
         else:
@@ -465,7 +483,8 @@ def validate_requires_arg(new_option, multi, requires, name):
             else:
                 ret_requires[action][inverse][0].append((option, [expected]))
 
-    def set_expected(require, ret_requires):
+    def set_expected(require,
+                     ret_requires):
         expected = require['expected']
         inverse = get_inverse(require)
         transitive = get_transitive(require)
@@ -484,7 +503,13 @@ def validate_requires_arg(new_option, multi, requires, name):
                         raise ValueError(_('malformed requirements expected value '
                                            'must be valid for option {0}'
                                            ': {1}').format(name, err))
-                _set_expected(action, inverse, transitive, same_action, option, exp['value'], operator)
+                _set_expected(action,
+                              inverse,
+                              transitive,
+                              same_action,
+                              option,
+                              exp['value'],
+                              operator)
         else:
             option = get_option(require)
             if expected is not None:
@@ -493,7 +518,13 @@ def validate_requires_arg(new_option, multi, requires, name):
                     raise ValueError(_('malformed requirements expected value '
                                        'must be valid for option {0}'
                                        ': {1}').format(name, err))
-            _set_expected(action, inverse, transitive, same_action, option, expected, operator)
+            _set_expected(action,
+                          inverse,
+                          transitive,
+                          same_action,
+                          option,
+                          expected,
+                          operator)
 
     def get_action(require):
         action = require['action']
@@ -572,123 +603,3 @@ def validate_requires_arg(new_option, multi, requires, name):
                                require[2], require[3], require[4], require[5]))
         ret.append(tuple(ret_action))
     return frozenset(config_action), tuple(ret)
-
-
-class SymLinkOption(OnlyOption):
-
-    def __init__(self,
-                 name,
-                 opt):
-        if not isinstance(opt, OnlyOption) or \
-                opt.impl_is_symlinkoption():
-            raise ValueError(_('malformed symlinkoption '
-                               'must be an option '
-                               'for symlink {0}').format(name))
-        _setattr = object.__setattr__
-        _setattr(self, '_name', name)
-        _setattr(self, '_opt', opt)
-        opt._add_dependency(self)
-
-    def impl_has_dependency(self, self_is_dep=True):
-        """If self_is_dep is True, it has dependency (self._opt), so return True
-        if self_is_dep is False, cannot has validation or callback, so return False
-        """
-        return self_is_dep is True
-
-    def impl_is_symlinkoption(self):
-        return True
-
-    def __getattr__(self, name, context=undefined):
-        return getattr(self.impl_getopt(), name)
-
-    def impl_getopt(self):
-        return self._opt
-
-    def impl_get_information(self, key, default=undefined):
-        return self.impl_getopt().impl_get_information(key, default)
-
-    def impl_is_readonly(self):
-        return True
-
-    def impl_getproperties(self):
-        return self.impl_getopt().impl_getproperties()
-
-    def impl_get_callback(self):
-        return self.impl_getopt().impl_get_callback()
-
-    def impl_has_callback(self):
-        "to know if a callback has been defined or not"
-        return self.impl_getopt().impl_has_callback()
-
-    def impl_is_multi(self):
-        return self.impl_getopt().impl_is_multi()
-
-    def _is_subdyn(self):
-        return getattr(self.impl_getopt(), '_subdyn', None) is not None
-
-    def _get_consistencies(self):
-        return ()
-
-    def _has_consistencies(self):
-        return False
-
-
-class DynSymLinkOption(object):
-    __slots__ = ('_rootpath', 
-                 '_opt',
-                 '_suffix')
-
-    def __init__(self,
-                 opt,
-                 rootpath,
-                 suffix):
-        self._opt = opt
-        self._rootpath = rootpath
-        self._suffix = suffix
-
-    def __getattr__(self,
-                    name,
-                    context=undefined):
-        return getattr(self.impl_getopt(), name)
-
-    def impl_getname(self):
-        return self._opt.impl_getname() + self._suffix
-
-    def impl_get_display_name(self):
-        return self.impl_getopt().impl_get_display_name(dyn_name=self.impl_getname())
-
-    def impl_getopt(self):
-        return self._opt
-
-    def impl_getsuffix(self):
-        return self._suffix
-
-    def impl_getpath(self,
-                     context):
-        if self._rootpath == '':
-            return self.impl_getname()
-        return self._rootpath + '.' + self.impl_getname()
-
-    def impl_validate(self,
-                      value,
-                      context=undefined,
-                      validate=True,
-                      force_index=None,
-                      is_multi=None,
-                      display_error=True,
-                      display_warnings=True,
-                      multi=None,
-                      setting_properties=undefined):
-        return self.impl_getopt().impl_validate(value,
-                                                context,
-                                                validate,
-                                                force_index,
-                                                current_opt=self,
-                                                is_multi=is_multi,
-                                                display_error=display_error,
-                                                display_warnings=display_warnings,
-                                                multi=multi,
-                                                setting_properties=setting_properties)
-
-    def impl_is_dynsymlinkoption(self):
-        return True
diff --git a/tiramisu/option/broadcastoption.py b/tiramisu/option/broadcastoption.py
index abafc45..f3fc8b8 100644
--- a/tiramisu/option/broadcastoption.py
+++ b/tiramisu/option/broadcastoption.py
@@ -31,7 +31,7 @@ class BroadcastOption(Option):
     _display_name = _('broadcast address')
 
     def _validate(self, value, context=undefined, current_opt=undefined):
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
         if value.count('.') != 3:
diff --git a/tiramisu/option/dateoption.py b/tiramisu/option/dateoption.py
index b368827..3e2b0ea 100644
--- a/tiramisu/option/dateoption.py
+++ b/tiramisu/option/dateoption.py
@@ -30,7 +30,7 @@ class DateOption(Option):
     _display_name = _('date')
 
     def _validate(self, value, context=undefined, current_opt=undefined):
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
         try:
diff --git a/tiramisu/option/domainnameoption.py b/tiramisu/option/domainnameoption.py
index dfe3552..3e12755 100644
--- a/tiramisu/option/domainnameoption.py
+++ b/tiramisu/option/domainnameoption.py
@@ -86,7 +86,7 @@ class DomainnameOption(Option):
             return 63
 
     def _validate(self, value, context=undefined, current_opt=undefined):
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
 
diff --git a/tiramisu/option/ipoption.py b/tiramisu/option/ipoption.py
index 306e6bb..d49297b 100644
--- a/tiramisu/option/ipoption.py
+++ b/tiramisu/option/ipoption.py
@@ -53,7 +53,7 @@ class IPOption(Option):
     def _validate(self, value, context=undefined, current_opt=undefined):
         # sometimes an ip term starts with a zero
         # but this does not fit in some case, for example bind does not like it
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
         if value.count('.') != 3:
diff --git a/tiramisu/option/netmaskoption.py b/tiramisu/option/netmaskoption.py
index dcd9ef0..4dc154e 100644
--- a/tiramisu/option/netmaskoption.py
+++ b/tiramisu/option/netmaskoption.py
@@ -32,7 +32,7 @@ class NetmaskOption(Option):
     _display_name = _('netmask address')
 
     def _validate(self, value, context=undefined, current_opt=undefined):
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
         if value.count('.') != 3:
diff --git a/tiramisu/option/networkoption.py b/tiramisu/option/networkoption.py
index 75f9e17..7733831 100644
--- a/tiramisu/option/networkoption.py
+++ b/tiramisu/option/networkoption.py
@@ -31,7 +31,7 @@ class NetworkOption(Option):
     _display_name = _('network address')
 
     def _validate(self, value, context=undefined, current_opt=undefined):
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
         if value.count('.') != 3:
diff --git a/tiramisu/option/option.py b/tiramisu/option/option.py
index 0e2389b..6705dfc 100644
--- a/tiramisu/option/option.py
+++ b/tiramisu/option/option.py
@@ -23,7 +23,8 @@ import warnings
 import sys
 import weakref
 
-from .baseoption import OnlyOption, submulti, DynSymLinkOption, validate_callback, STATIC_TUPLE
+from .baseoption import OnlyOption, submulti, validate_callback, STATIC_TUPLE
+from .symlinkoption import DynSymLinkOption
 from ..i18n import _
 from ..setting import log, undefined, debug
 from ..autolib import carry_out_calculation
@@ -746,7 +747,7 @@ class RegexpOption(Option):
                   value,
                   context=undefined,
                   current_opt=undefined):
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
         match = self._regexp.search(value)
diff --git a/tiramisu/option/passwordoption.py b/tiramisu/option/passwordoption.py
index 15b8a86..38d8f5b 100644
--- a/tiramisu/option/passwordoption.py
+++ b/tiramisu/option/passwordoption.py
@@ -30,6 +30,6 @@ class PasswordOption(Option):
     _display_name = _('password')
 
     def _validate(self, value, context=undefined, current_opt=undefined):
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
diff --git a/tiramisu/option/portoption.py b/tiramisu/option/portoption.py
index c810d36..6f55252 100644
--- a/tiramisu/option/portoption.py
+++ b/tiramisu/option/portoption.py
@@ -87,7 +87,7 @@ class PortOption(Option):
                 value = str(value)
             else:
                 value = unicode(value)
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
         if self._get_extra('_allow_range') and ":" in str(value):
diff --git a/tiramisu/option/symlinkoption.py b/tiramisu/option/symlinkoption.py
new file mode 100644
index 0000000..2ffc222
--- /dev/null
+++ b/tiramisu/option/symlinkoption.py
@@ -0,0 +1,147 @@
+# -*- coding: utf-8 -*-
+# Copyright (C) 2017 Team tiramisu (see AUTHORS for all contributors)
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as published by the
+# Free Software Foundation, either version 3 of the License, or (at your
+# option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# The original `Config` design model is unproudly borrowed from
+# the rough pypy's guys: http://codespeak.net/svn/pypy/dist/pypy/config/
+# the whole pypy projet is under MIT licence
+# ____________________________________________________________
+from .baseoption import OnlyOption
+from ..i18n import _
+from ..setting import undefined
+
+
+class SymLinkOption(OnlyOption):
+
+    def __init__(self,
+                 name,
+                 opt):
+        if not isinstance(opt, OnlyOption) or \
+                opt.impl_is_symlinkoption():
+            raise ValueError(_('malformed symlinkoption '
+                               'must be an option '
+                               'for symlink {0}').format(name))
+        _setattr = object.__setattr__
+        _setattr(self, '_name', name)
+        _setattr(self, '_opt', opt)
+        opt._add_dependency(self)
+
+    def impl_has_dependency(self, self_is_dep=True):
+        """If self_is_dep is True, it has dependency (self._opt), so return True
+        if self_is_dep is False, cannot has validation or callback, so return False
+        """
+        return self_is_dep is True
+
+    def impl_is_symlinkoption(self):
+        return True
+
+    def __getattr__(self,
+                    name,
+                    context=undefined):
+        return getattr(self.impl_getopt(), name)
+
+    def impl_getopt(self):
+        return self._opt
+
+    def impl_get_information(self,
+                             key,
+                             default=undefined):
+        return self.impl_getopt().impl_get_information(key, default)
+
+    def impl_is_readonly(self):
+        return True
+
+    def impl_getproperties(self):
+        return self.impl_getopt().impl_getproperties()
+
+    def impl_get_callback(self):
+        return self.impl_getopt().impl_get_callback()
+
+    def impl_has_callback(self):
+        "to know if a callback has been defined or not"
+        return self.impl_getopt().impl_has_callback()
+
+    def impl_is_multi(self):
+        return self.impl_getopt().impl_is_multi()
+
+    def _is_subdyn(self):
+        return getattr(self.impl_getopt(), '_subdyn', None) is not None
+
+    def _get_consistencies(self):
+        return ()
+
+    def _has_consistencies(self):
+        return False
+
+
+class DynSymLinkOption(object):
+    __slots__ = ('_rootpath', 
+                 '_opt',
+                 '_suffix')
+
+    def __init__(self,
+                 opt,
+                 rootpath,
+                 suffix):
+        self._opt = opt
+        self._rootpath = rootpath
+        self._suffix = suffix
+
+    def __getattr__(self,
+                    name,
+                    context=undefined):
+        return getattr(self.impl_getopt(), name)
+
+    def impl_getname(self):
+        return self._opt.impl_getname() + self._suffix
+
+    def impl_get_display_name(self):
+        return self.impl_getopt().impl_get_display_name(dyn_name=self.impl_getname())
+
+    def impl_getopt(self):
+        return self._opt
+
+    def impl_getsuffix(self):
+        return self._suffix
+
+    def impl_getpath(self,
+                     context):
+        if self._rootpath == '':
+            return self.impl_getname()
+        return self._rootpath + '.' + self.impl_getname()
+
+    def impl_validate(self,
+                      value,
+                      context=undefined,
+                      validate=True,
+                      force_index=None,
+                      is_multi=None,
+                      display_error=True,
+                      display_warnings=True,
+                      multi=None,
+                      setting_properties=undefined):
+        return self.impl_getopt().impl_validate(value,
+                                                context,
+                                                validate,
+                                                force_index,
+                                                current_opt=self,
+                                                is_multi=is_multi,
+                                                display_error=display_error,
+                                                display_warnings=display_warnings,
+                                                multi=multi,
+                                                setting_properties=setting_properties)
+
+    def impl_is_dynsymlinkoption(self):
+        return True
diff --git a/tiramisu/option/syndynoptiondescription.py b/tiramisu/option/syndynoptiondescription.py
index 85d8a96..5298fb2 100644
--- a/tiramisu/option/syndynoptiondescription.py
+++ b/tiramisu/option/syndynoptiondescription.py
@@ -20,7 +20,7 @@
 # ____________________________________________________________
 from ..i18n import _
 from ..setting import undefined
-from .baseoption import DynSymLinkOption
+from .symlinkoption import DynSymLinkOption
 
 
 class SynDynOptionDescription(object):
diff --git a/tiramisu/option/urloption.py b/tiramisu/option/urloption.py
index 65daf6f..c5fb989 100644
--- a/tiramisu/option/urloption.py
+++ b/tiramisu/option/urloption.py
@@ -33,7 +33,7 @@ class URLOption(DomainnameOption):
     _display_name = _('URL')
 
     def _validate(self, value, context=undefined, current_opt=undefined):
-        err = self._impl_valid_unicode(value)
+        err = self._impl_valid_string(value)
         if err:
             return err
         match = self.proto_re.search(value)